strict_isna <- function(x){
  if(is.null(x)){
    return(T)
  }else if(length(x) == 0){
    return(T)
  }else if(is.na(x)){
    return(T)
  }else if(x == ""){
    return(T)
  }else{
    return(F)
  }
}

####Test Area####

# strict_isna("")
# strict_isna(NA)
# strict_isna(NULL)
# strict_isna(1)
# strict_isna("a")
# a = c(1, 2, 3)
# strict_isna(a[a == 5])
